/**
 * MD5 Hash Implementation
 * A JavaScript implementation of the RSA Data Security, Inc. MD5 Message
 * Digest Algorithm, as defined in RFC 1321.
 */

function md5(string) {
  function rotateLeft(value, amount) {
    return (value << amount) | (value >>> (32 - amount));
  }

  function addUnsigned(x, y) {
    const x4 = (x & 0x40000000);
    const y4 = (y & 0x40000000);
    const x8 = (x & 0x80000000);
    const y8 = (y & 0x80000000);
    const result = (x & 0x3FFFFFFF) + (y & 0x3FFFFFFF);
    
    if (x4 & y4) {
      return (result ^ 0x80000000 ^ x8 ^ y8);
    }
    if (x4 | y4) {
      if (result & 0x40000000) {
        return (result ^ 0xC0000000 ^ x8 ^ y8);
      } else {
        return (result ^ 0x40000000 ^ x8 ^ y8);
      }
    } else {
      return (result ^ x8 ^ y8);
    }
  }

  function f(x, y, z) {
    return (x & y) | ((~x) & z);
  }

  function g(x, y, z) {
    return (x & z) | (y & (~z));
  }

  function h(x, y, z) {
    return (x ^ y ^ z);
  }

  function i(x, y, z) {
    return (y ^ (x | (~z)));
  }

  function ff(a, b, c, d, x, s, ac) {
    a = addUnsigned(a, addUnsigned(addUnsigned(f(b, c, d), x), ac));
    return addUnsigned(rotateLeft(a, s), b);
  }

  function gg(a, b, c, d, x, s, ac) {
    a = addUnsigned(a, addUnsigned(addUnsigned(g(b, c, d), x), ac));
    return addUnsigned(rotateLeft(a, s), b);
  }

  function hh(a, b, c, d, x, s, ac) {
    a = addUnsigned(a, addUnsigned(addUnsigned(h(b, c, d), x), ac));
    return addUnsigned(rotateLeft(a, s), b);
  }

  function ii(a, b, c, d, x, s, ac) {
    a = addUnsigned(a, addUnsigned(addUnsigned(i(b, c, d), x), ac));
    return addUnsigned(rotateLeft(a, s), b);
  }

  function convertToWordArray(string) {
    let wordCount;
    const messageLength = string.length;
    const numberOfWordsTemp1 = messageLength + 8;
    const numberOfWordsTemp2 = (numberOfWordsTemp1 - (numberOfWordsTemp1 % 64)) / 64;
    const numberOfWords = (numberOfWordsTemp2 + 1) * 16;
    const wordArray = new Array(numberOfWords - 1);
    let bytePosition = 0;
    let byteCount = 0;
    
    while (byteCount < messageLength) {
      wordCount = (byteCount - (byteCount % 4)) / 4;
      bytePosition = (byteCount % 4) * 8;
      wordArray[wordCount] = (wordArray[wordCount] | (string.charCodeAt(byteCount) << bytePosition));
      byteCount++;
    }
    
    wordCount = (byteCount - (byteCount % 4)) / 4;
    bytePosition = (byteCount % 4) * 8;
    wordArray[wordCount] = wordArray[wordCount] | (0x80 << bytePosition);
    wordArray[numberOfWords - 2] = messageLength << 3;
    wordArray[numberOfWords - 1] = messageLength >>> 29;
    
    return wordArray;
  }

  function wordToHex(value) {
    let wordToHexValue = "";
    let wordToHexValueTemp = "";
    let byte, count;
    
    for (count = 0; count <= 3; count++) {
      byte = (value >>> (count * 8)) & 255;
      wordToHexValueTemp = "0" + byte.toString(16);
      wordToHexValue = wordToHexValue + wordToHexValueTemp.substr(wordToHexValueTemp.length - 2, 2);
    }
    
    return wordToHexValue;
  }

  function utf8Encode(string) {
    string = string.replace(/\r\n/g, "\n");
    let utftext = "";
    
    for (let n = 0; n < string.length; n++) {
      const c = string.charCodeAt(n);
      
      if (c < 128) {
        utftext += String.fromCharCode(c);
      } else if ((c > 127) && (c < 2048)) {
        utftext += String.fromCharCode((c >> 6) | 192);
        utftext += String.fromCharCode((c & 63) | 128);
      } else {
        utftext += String.fromCharCode((c >> 12) | 224);
        utftext += String.fromCharCode(((c >> 6) & 63) | 128);
        utftext += String.fromCharCode((c & 63) | 128);
      }
    }
    
    return utftext;
  }

  let x = [];
  let k, AA, BB, CC, DD, a, b, c, d;
  const S11 = 7, S12 = 12, S13 = 17, S14 = 22;
  const S21 = 5, S22 = 9, S23 = 14, S24 = 20;
  const S31 = 4, S32 = 11, S33 = 16, S34 = 23;
  const S41 = 6, S42 = 10, S43 = 15, S44 = 21;

  string = utf8Encode(string);
  x = convertToWordArray(string);
  a = 0x67452301;
  b = 0xEFCDAB89;
  c = 0x98BADCFE;
  d = 0x10325476;

  for (k = 0; k < x.length; k += 16) {
    AA = a;
    BB = b;
    CC = c;
    DD = d;
    a = ff(a, b, c, d, x[k + 0], S11, 0xD76AA478);
    d = ff(d, a, b, c, x[k + 1], S12, 0xE8C7B756);
    c = ff(c, d, a, b, x[k + 2], S13, 0x242070DB);
    b = ff(b, c, d, a, x[k + 3], S14, 0xC1BDCEEE);
    a = ff(a, b, c, d, x[k + 4], S11, 0xF57C0FAF);
    d = ff(d, a, b, c, x[k + 5], S12, 0x4787C62A);
    c = ff(c, d, a, b, x[k + 6], S13, 0xA8304613);
    b = ff(b, c, d, a, x[k + 7], S14, 0xFD469501);
    a = ff(a, b, c, d, x[k + 8], S11, 0x698098D8);
    d = ff(d, a, b, c, x[k + 9], S12, 0x8B44F7AF);
    c = ff(c, d, a, b, x[k + 10], S13, 0xFFFF5BB1);
    b = ff(b, c, d, a, x[k + 11], S14, 0x895CD7BE);
    a = ff(a, b, c, d, x[k + 12], S11, 0x6B901122);
    d = ff(d, a, b, c, x[k + 13], S12, 0xFD987193);
    c = ff(c, d, a, b, x[k + 14], S13, 0xA679438E);
    b = ff(b, c, d, a, x[k + 15], S14, 0x49B40821);
    a = gg(a, b, c, d, x[k + 1], S21, 0xF61E2562);
    d = gg(d, a, b, c, x[k + 6], S22, 0xC040B340);
    c = gg(c, d, a, b, x[k + 11], S23, 0x265E5A51);
    b = gg(b, c, d, a, x[k + 0], S24, 0xE9B6C7AA);
    a = gg(a, b, c, d, x[k + 5], S21, 0xD62F105D);
    d = gg(d, a, b, c, x[k + 10], S22, 0x2441453);
    c = gg(c, d, a, b, x[k + 15], S23, 0xD8A1E681);
    b = gg(b, c, d, a, x[k + 4], S24, 0xE7D3FBC8);
    a = gg(a, b, c, d, x[k + 9], S21, 0x21E1CDE6);
    d = gg(d, a, b, c, x[k + 14], S22, 0xC33707D6);
    c = gg(c, d, a, b, x[k + 3], S23, 0xF4D50D87);
    b = gg(b, c, d, a, x[k + 8], S24, 0x455A14ED);
    a = gg(a, b, c, d, x[k + 13], S21, 0xA9E3E905);
    d = gg(d, a, b, c, x[k + 2], S22, 0xFCEFA3F8);
    c = gg(c, d, a, b, x[k + 7], S23, 0x676F02D9);
    b = gg(b, c, d, a, x[k + 12], S24, 0x8D2A4C8A);
    a = hh(a, b, c, d, x[k + 5], S31, 0xFFFA3942);
    d = hh(d, a, b, c, x[k + 8], S32, 0x8771F681);
    c = hh(c, d, a, b, x[k + 11], S33, 0x6D9D6122);
    b = hh(b, c, d, a, x[k + 14], S34, 0xFDE5380C);
    a = hh(a, b, c, d, x[k + 1], S31, 0xA4BEEA44);
    d = hh(d, a, b, c, x[k + 4], S32, 0x4BDECFA9);
    c = hh(c, d, a, b, x[k + 7], S33, 0xF6BB4B60);
    b = hh(b, c, d, a, x[k + 10], S34, 0xBEBFBC70);
    a = hh(a, b, c, d, x[k + 13], S31, 0x289B7EC6);
    d = hh(d, a, b, c, x[k + 0], S32, 0xEAA127FA);
    c = hh(c, d, a, b, x[k + 3], S33, 0xD4EF3085);
    b = hh(b, c, d, a, x[k + 6], S34, 0x4881D05);
    a = hh(a, b, c, d, x[k + 9], S31, 0xD9D4D039);
    d = hh(d, a, b, c, x[k + 12], S32, 0xE6DB99E5);
    c = hh(c, d, a, b, x[k + 15], S33, 0x1FA27CF8);
    b = hh(b, c, d, a, x[k + 2], S34, 0xC4AC5665);
    a = ii(a, b, c, d, x[k + 0], S41, 0xF4292244);
    d = ii(d, a, b, c, x[k + 7], S42, 0x432AFF97);
    c = ii(c, d, a, b, x[k + 14], S43, 0xAB9423A7);
    b = ii(b, c, d, a, x[k + 5], S44, 0xFC93A039);
    a = ii(a, b, c, d, x[k + 12], S41, 0x655B59C3);
    d = ii(d, a, b, c, x[k + 3], S42, 0x8F0CCC92);
    c = ii(c, d, a, b, x[k + 10], S43, 0xFFEFF47D);
    b = ii(b, c, d, a, x[k + 1], S44, 0x85845DD1);
    a = ii(a, b, c, d, x[k + 8], S41, 0x6FA87E4F);
    d = ii(d, a, b, c, x[k + 15], S42, 0xFE2CE6E0);
    c = ii(c, d, a, b, x[k + 6], S43, 0xA3014314);
    b = ii(b, c, d, a, x[k + 13], S44, 0x4E0811A1);
    a = ii(a, b, c, d, x[k + 4], S41, 0xF7537E82);
    d = ii(d, a, b, c, x[k + 11], S42, 0xBD3AF235);
    c = ii(c, d, a, b, x[k + 2], S43, 0x2AD7D2BB);
    b = ii(b, c, d, a, x[k + 9], S44, 0xEB86D391);
    a = addUnsigned(a, AA);
    b = addUnsigned(b, BB);
    c = addUnsigned(c, CC);
    d = addUnsigned(d, DD);
  }

  const temp = wordToHex(a) + wordToHex(b) + wordToHex(c) + wordToHex(d);
  return temp.toLowerCase();
}

// Export for different module systems
if (typeof module !== 'undefined' && module.exports) {
  module.exports = md5;
  module.exports.md5 = md5;
} else if (typeof define === 'function' && define.amd) {
  define(function() {
    return md5;
  });
} else {
  // For browser or uni-app environment
  if (typeof window !== 'undefined') {
    window.md5 = md5;
  }
  // For uni-app
  if (typeof global !== 'undefined') {
    global.md5 = md5;
  }
}

// ES6 exports
export default md5;
export { md5 };